Atopy is a predisposition toward developing certain allergic hypersensitivity reactions. Atopy may have a hereditary component, although contact with the allergen or irritant must occur before the hypersensitivity reaction can develop.
As of 2012, 63.9 percent of players playing in Major League Baseball are white. There is no way of telling the exact number due to the number of players.
Location of Puerto Rico's main island (green) Puerto Rico currently has the fourth-most active players in Major League Baseball (MLB) among Latin American jurisdictions, behind the Dominican Republic, Venezuela, and Cuba. More than two hundred players from the archipelago have played in the major leagues since 1942.